Denny... my first job after high school was in Marengo... that was in ... ah... 1966 and that's a long story...
Now... back to the engine: I followed your procedure and did the adjustment with the engine running. Made a HUGE difference.
Set the timing to about 14* before tdc and she is developing power like before the rod broke.

New problem: Will not idle with A/C on and engine at running temp. After it dies, it is really hard to start.. like it has a hard time turning over. After a brief cooldown it starts and runs fine as long as A/C stays off. I can "feather" the gas pedal and keep it running. Any ideas?